Add support for max_artifacts_size for groups and projects

Add the max_artifacts_size parameter to the group and project edit APIs.

Implementation Guide

• Read the CONTRIBUTING.md guide for setting up your local development environment and clone the community fork of this project.
• In groups.go add MaxArtifactsSize to the Group and UpdateGroupOptions structs.
• In projects.go add MaxArtifactsSize to the Project and EditProjectOptions structs.
• Update unit tests for both files to use the new field.
• Ideally, add an integration test for the get and update group/project endpoints using the new field.